We have reproduced the issue. We are investigating it now. We will inform you about the results as soon as possible. As a temporary workaround, you can try using operations with the TimeSpan.
For example, to select rows, where the difference between the dates is more than 60 minutes, use:

We have investigated this issue. The DateDiffMinute method (as well as DateDiffMonth, DateDiffSecond and others) is bound to the SQL Server's DateDiff() built-in function, which is not available in other DBMSs (e.g., in PostgreSQL). Thus, we are not planning to support these methods in the nearest future. Instead, you can use the way we have offered you earlier.